We describe a simple process for prepare three-dimensional porous silicon powders by acid etching process. Subsequently, the aluminum-silicon alloy particles were chemically etched to synthesize porous silicon particles, without changing the chemical and physical properties of Si. The silicon monoxide-coated porous silicon anodes exhibited excellent electrochemical properties, including a high specific capacity and a high rate capability. High electrochemical performance of porous silicon powder could be attributed to its porous structure, which provides enough tiny space to buffer the huge volume change of Si anode during charging and discharging processes. The firm connection between Si nanobars in spongy porous structure prevented the breakdown of porous Si particles. This easy acid etching process for preparing high performance porous Si material is simple and inexpensive, effective way for a rich variety of applications, including lithium-ion batteries.